Resettable clock or the like



A. w. HAYDON 3,233,400

RESETTABLE CLOCK OR THE LIKE 3 Sheets-Sheet 1 Feb. 8, 1966 Filed Oct.21, 1963 INVENTOR. ARTHUR W. HAYDON {.JJ w ATTORNEYS Feb. 8, 1966 A. w.HAYDON 3,233,400

RESET'IABLE CLOCK OR THE LIKE FIG. 4

FIG. 3

INVENTOR. 93 ARTHUR W. HAYDQN ATTORNE YS Feb. 8, 1966 A. w. HAYDONRESETTABLE CLOCK OR THE LIKE 5 Sheets-Sheet 5 Filed Oct. 21, 1963 FIG. 5

INVENTOR. ARTHUR W. HAYDON ATTORNE S United States Patent Ofiice3,233,400 Patented Feb. 8, 1966 3,233,400 RESETTABLE CLOCK OR THE LIKEArthur W. Haydon, 83 Point Lookout, Milford, Conn. Filed Oct. 21, 1963,Ser. No. 317,419 21 Claims. (Cl. 58--34) The present invention relatesto a resettable clock mechanism or the like, and is intendedspecifically for, although not necessarily limited to, a novel andimproved resettable clock mechanism for incorporation in a masterslavetimekeeping system, whereby one or more slave clock units mayperiodically be reset to a predetermined time indication andsubsequently restarted in synchronous relation with a precisoncontrolled master timing unit.

A; variety of timekeeping systems are presently known and availablewhich make use of a master timekeeping unit and a plurality of slavetimekeeping units, and in whicli'theslave units periodically arecorrected to coincide exactly with the timekeeping of the master unit.Such timekeeping systems find advantageous use for accurate timenetworks, for example, where the master timekeeping unit is maintainedaccurately related to standard or observatory time; likewise, thesystems may be employed to advantage to provide plant-wide orcomrelation with a precision controlled master timing unit. formity oftimekeeping is desired, as for punch clocks and the like.

In accordance with the present invention, a novel and improvedmechanical mechanism is provided, for particular application as a slaveunit in a master-slave timekeeping system, which is of extremelysimplified and economical construction, while at the same time beinghighly reliable in operation. Thus, in accordance with one aspect of theinvention, a novel timekeeping mechanism or the like is provided whichcomprises a plurality of output shafts connected through a predeterminedgear reduction mechanism for operation at related speeds (e.g., hourhand and minute hand) in which means are provided for controllablydisengaging the output shafts from their respective drive mechanisms toaccommodate free rotation of the shafts, and additional means areprovided for acting upon the disengaged shafts to return them topredetermined, time-indicating positions, from which they may berestarted in accurately synchronized relation to a master timekeepingdevice. Thus, the clock of the invention is intended specifically to bereset once during each twelve hour or twenty-four hour period, forexample, at which time the hands of the slave timekeeping units arereset to a; specific, predesignated time. Thereafter, upon signal fromthe master timekeeping device, the clock is restarted from suchpredesignated time.

One of the more specific aspects of the invention resides in theprovision, in a clock or similar mechanism incorporating a substantialgear reduction train, of means for controllably disengaging a pluralityof output shafts from driving relation with the gear reduction train,e11- abling the output shafts to be reset individually to predeterminedrotary positions, while at the same time maintaining the output shaftsand gear reduction train in a synchronized relationship, accommodatingsmooth remeshing of the various gears upon re-engagement of the gearreduction train. This advantageous result is achieved, in accordancewith the invention, by providing novel and simplified arrangements fordisengaging certain gears of the train, while maintaining other gears inmesh, and by so designing the disengaged gears, in relation to thevarious gear reductions involved in the gear train, that properalignment of the disengaged gear pairs is assured, even though theoutput shafts of the mechanism are returned independently topredetermined positions.

Another specific aspect of the invention resides in the provision ofnovel magnetic reset means, including polarized magnets of specificallynovel form acting between fixed parts of the mechanism frame and therespective output shafts and operative, when the output shafts aredisengaged from the gear reduction train, to urge the shaftsindividually to rotate into precise, predetermined rotary resetpositions. The magnetic reset facilities constantly influence the outputshafts of the mechanism, without involving any actual physical contactbetween parts and without affecting the normal operation of the clock.However, when the outut shafts are disengaged from the driving train andare capable of free rotation, the polarized magnet pairs immediatelyreturn the shafts individually to their predetermined reset positions.

As a further specific aspect of the invention, a resettable clock orsimilar mechanism is provided, which includes novel and simplified resetshift means, whereby the output shafts of the mechanism may bedisengaged from the driving gear train to accommodate independentresetting rotary movement of the various output shafts. The mechanism ofthe invention includes a movable member, for shifting selected gears ofthe reduction train out of driving mesh, and a solenoid for controllingthe shifting movements of the member, The solenoid is actuated inconjunction with the actuation of an input electric motor for themechanism, such that the solenoid is actuated to effect engagement ofthe drive system when the motor is energized, and the solenoid isde-energized to effect disengagement of the reduction train when theinput motor is de-energized. However, in accordance with the invention,the work input necessary to effect engagement and. disengagement of thereduction train is not derived from the solenoid, but is derived fromthe motor itself. Significantly, this avoids the necessity for thesolenoid doing work during its closing or energizing movements, enablinga small and inexpensive solenoid to be employed.

In conjunction with the above-described novel reset shift arrangement,the mechanism of the invention carries a unique magnetic detentarrangement whereby the reset shift mechanism, when driven into apredetermined position by the input motor, passes through an overcenterposition and is advanced further and held in an operative conditionthrough the cooperation of a magnetic detent arrangement and the resetsolenoid. Subsequently, when the mechanism is released by the solenoid,the magnetic detent arrangement serves to advance the mechanism into aposition in which it is drivingly engaged with the input motor, inreadiness for a restarting operation.

For a better understanding of the above and other novel and advantageousfeatures of the invention, reference should be made to the followingdetailed description and to the accompanying drawings, in'which:

FIG. 1 is a longitudinal cross-sectional view of a slave timekeepingmechanism incorporating the various features of the invention;

FIG. 2 is a back elevation of the mechanism of FIG. 1, with the coverremoved and with parts broken away for clarity of illustration;

FIG. 3 is an enlarged, fragmentary, cross-sectional view taken generallyalong line 33 of FIG. 1 illustrating the mechanism in an operating orengaged condition;

FIG. 4 is an enlarged, fragmentary, cross-sectional view similar to FIG.3, illustrating parts of the mechanism in a reset or disengagedcondition;

FIG. 5 is an enlarged, fragmentary, cross-sectional vie/w takengenerally along line 5-5 of FIG. 1; and

FIG. 6 is a simplified, schematic representation of an electricalcircuit arrangement employed in the control of the mechanism of FIG. 1.

Referring now to the drawings, and initially to FIG. 1 thereof, thereference numerals 12 designate frame plates which are connectedtogether in a conventional manner by spacer posts 13 and bolts 14 toform a rigid, three-dimensional frame structure. An indicator, such as aclock face 15, is secured to the front frame plate 10, and a cover orhousing 16 surrounds the entire frame and the mechanism containedtherein.

The specific mechanism illustrated is a slave clock unit provided withsecond, minute, and hour hands 17-19 mounted respectively on concentricshafts 2042. The innermost or second hand shaft 20 may be a solid,elongated shaft and advantageously is journalled in an elongated tubularbearing 23 anchored at its innermost end in the frame plate 11 andprojecting forlward beyond the clock face 15. The intermediate or minutehand shaft 21 is of tubular form and of shorter length than the secondhand shaft 20, and is so constructed as to. surround and be supportedinternally by the tubular bearing 23. The hour hand shaft 22 surroundsthe minute hand shaft 21 and is supported for rotation by ananti-\friction-bearing 24 mounted in the front plate 10 of the framestructure. The respective shafts 2022, referred to herein as outputshafts, are of graduated length, such that the minute hand shaft 21projects beyond both ends of the hour hand shaft and the second handshaft 20 projects beyond both ends of the minute hand shaft, all inaccordance with known principles of clock construction.

Each of the output shafts 20 22 has securedlto its inner end a drivegear, designated bythe numerals 25-27. Likewise, each of the higherspeed output shafts, that is, the second hand shaft 20 and the minutehand shaft 21, carries a reduction pinion, the latter beingdesignated bythe reference numerals 28, 29.

In a typical clock mechanism, the second hand shaft \20 is driven at arate of one revolution per minute, by appropriate input to the drivegear 25. The minute hand shaft 21 is designed to rotate at a'rate of onerevolution per hour, and this-is brought about by effecting a 60:1

gear reduction ratio between the second hand shaft 20 and the minutehand shaftZI. To this end, the reduction pinion 28, attached to theinner end of the second hand shaft 20, drives a gear a of a gear andpinion speed reduction combination 30, while the pinion 3-1 of thecombination engages the drive gear 26 for the minute hand shaft. The twospeed reductions derived through the .gears .28, 30a and the gears 31,26 are so calculated as to achieve the desired-60:1 reduction ratio.

Likewise, the hour hand shaft 22 of the clock mechanism is designed torotate at a rate of one revolution for each twelve (or in some casestwenty-four) hours, and this is achieved by employing a second gear andpinion speed reduction combination 32, with the gear 33 of thecombination meshing with the reduction pinion 29 carried by the minutehand shaft and the pinion 34 of the combinationmeshing with the. drivegear 27 of the hour hand shaft 22. i

V For driving the gear 25 and'the second hand shaft 20, thereadvantageously is provided an input drive motor 35, which is secured tothe back frame plate 12 and has its rotor shaft 36 and output pinion 37projecting forward through the frame plate. Advantageously, the motor isa synchronous inductor motor of the general type described and claimedin the W. D. Riggs Patent No. 3,014,141, granted December 19, 1961,'and,in any event, is of a type that, when de-energized, stops immediatelythrough residual magnetic effects or otherwise, and then drives a speedreduction combination 38, including a gear 39 and pinion 40, and thepinion 40, in turn, drives a further speed reduction combination 41,including a gear 42 and pinion 43. 1 The pinion 43 meshes withthe drivegear 25 fixed to the end of the second hand shaft 20.

In a typical, practical embodiment o-fthe invention, the motor 35 may bedesigned for synchronous operations at 250 revolutions per minute. Insuch case, the three speed reduction steps achieved through the gears 37and 39, and 42, and 43 and 25 are calculated to provide the desiredoverall speed reduction of 250:1. Thus, in normal operation of themechanism for ordinary timekeeping purposes, the input motor 35,properly energized from an alternating current source, operates at 250r.p.rn. to drive the second hand shaft 20 at. one revolution per minute.The minute hand and hour hand shafts 21, 22 are correspondingly driventhrough their respective gear reduction trains at one revolution perhour and one revolution per twelve (or twenty-four) hours. a

In accordance with the invention, means are provided for controllablydisengaging the output shafts 2022 from their respective drivingmechanisms, to enable the respec tive shafts to be rotatedindividuallyto predetermined reset positions. To this end, therespective gear and pinion reduction combinations 32, 30, and 41, fordriving the hour, minute, and second hand shafts respectively, areretractably mounted on a common reset shift con trol shaft 44, thevarious gear and pinion combinations being freely and independentlyrotatable on the shaft. The control shaft '44 is provided at each endwitheccentrically positioned journal pins '45, which are received inbearings 46 in the front and rear frame plates 10, 1'2.-

. In a typical, practical embodiment of the invention, the

journal pins 45 may be offset approximately 0.010 inch from thecenterline of the control shaft 44 such that, when the control shaft isrotated through its centerline, which forms the rotational axis for therespectivespeed reduction gear and pinion combinations 32, 30, 41, areshifted through a total displacement of about 0.020 inch. Thus, byappropriate design of at least certain of the gears of the mechanism,disengagement of the respective output shafts from the gear mechanismmay be effected by rotating the control shaft 44 through approximately180 to displace its axis away from the common axis of the output shafts.When this is done, the output shafts are freely and independentlyrotatable, and, by means subsequently to be described, the respectiveoutput shafts are then returned to predetermined rotary reset positions.I

In accordance with one of the significant aspectsof. the invention, thevarious gear mechanisms involved in the driving of the output shafts areso designed and re-v lated that, when the output shafts aredisengagedand. returned to their respective reset positions, the various.cooperating gear sets are properly oriented for remeshing. Thus, whenthe control shaft 44 subsequently is rotated.

back through 180 to displace the control shaft axis to-.

output shafts 20-22 have a predetermined mutual relationship,corresponding to a relationship which the shafts would have ifinterconnected by the gear reduction train;

Thus, for descriptive purposes, with respect to a clock mechanism as anillustrated form .of the mechanism th'e' respective reset positions ofthe. output shafts must be" valid timekeeping positions, asdistinguished from posi-' tions which cannot be assumed by .the.hands ofa nor-j mally functioning clock.' As an illustration, the reset,positions may be such that all of the hands 17.1 9 .point directly totwelve oclock, although, as a practical matter,

it usually is desirable to effect reset at some less prominenti timethan exactly twelve oclock. Of course, it should be undestood .that'thenecessary mutual relationship for proper reset 'is essentially betweenthe output shafts themselves and not the time indicating hands 17-19,which may be adjustably related to the output shafts. However, assumingthe indicator hands to be properly adjusted nets 50b, 51b convenientlymay be mounted upon the intermediate frame plate 11, while the fixedmagnet 52b is conveniently mountedon the front frame plate 10.

, Each of the magnet pairs 5011-5011, 51a-51b, etc., is sharplypolarized, such that the movable magnet of each pair is urged into apredetermined rotary orientation relative to the fixed magnet.Thus,.when an output shaft is disconnected from the gear train, bymanipulation of the control shaft 44, the shaft is rotated under theinfluence of the associated magnet pair, until the magnets are alignedin their most strongly attracting relationship, which will determine thepredetermined rotationalorientation of the shaft in its reset position.

Initial alignment of the respective magnet pairs should be elfectedwhile the various output shafts are engaged with the reduction train, sothat all output shafts have an aligned or reset position which isconsistent with proper meshing of all gears of the train. With theoutput shaft locked in such position, the indicating hands or pointers17-19 may be adjusted to a desired orientation which, in the case of aclock, must be a valid timekeeping position. Thereafter, when therespective output shafts are released through manipulation of thecontrol shaft 44, each of the shafts will be rotated independently byits polarized magnet pair into its reset position, in which therespective shafts are in condition to be reengaged with the gear trainby operation of the control shaft 44. In the case of a clock, it isdesirable that the reset position of the hands17-19 be at a selected,nonprominent time of day or night, so that the clock can be reset to apredetermined start position, in accordance with a master clock signalat some time when the clock is least apt to be under observation. Thus,the reset time preferably is not on or particularly close to an evenhour, half hour, or quarter hour.

It is of significance that the respective polarized magnet pairs bequite sharply polarized, so that the respective output shafts are drawnwith considerable accuracy into their predetermined reset'positions and,in addition, so that the range of rotational orientation in which themagnet pairs are on dead center positions (oriented approximately 180out of reset position but without sufficient effective torque toinitiate thereset movement) is minimizedr, To this end, and as aspecific feature of the invention, it is. advantageous to employ magnetsof generally rectangular effective configuration, having poles or fluxconcentrators disposed at right angles to a polar axis extendingdiametrically through the shaft. This configuration, illustratedparticularly in FIG. 5,provides for especially sharp alignment of theflux concentrators of the, magnets of a cooperative pair, since a slightrotary displacement or misalignment of the flux concentrators will'causethe concentrator elements to be offset in a generally linear directionand 'also to be disposed at an angle, resulting in a highly effectiverestoring force being exerted uponthe shaft to return it to its resetposition. Thus, by way of example only, in a practical embodiment of theinvention utilizing generally linear fiux concentrators of about /2 inchin length, disposed at right angles to the polar axis, at a distance ofabout /2 inch from the center of the shaft,- the-resetting accuracy ofthe polarized magnets is reliably within a fraction of a degree, suchthat proper alignment of the various gears after reset is reliablyassured. Moreover, the range of dead center positions is so minute as topreclude, at least in a clock mechanism, the possibility of the outputshafts failing to be reset with complete reliability. In this respect,the inherent nature of aclock mechanism is such that there can be noposition in which all three of the resetting magnetpairs are indead'center positions. Thus, under all circumstances, at least one ofthe output shafts inherently will start toward its reset posiiton whenthe shafts are disengaged from the reduction gear train. And, eventhough one of the other shafts occasionally (statistically, rarely) maybe in a dead center condition at the start of reset, the minutevibrational motions involved in the resetting of the other shafts havebeen shown to be sufficient to displace a shaft from its dead centercondition and assure its reliable return to reset position.

Referring specifically to FIG. 5, the polarized magnet 51a is shown indetail, it being understood that the illustrated magnet isrepresentative of the others. Advantageously, the magnet includes a pairof pole pieces or flux concentrators 54, 55 of generally L-shaped crosssection, which are secured to one face of the drive gear 26, in suchmanner that outer legs of the L project axially outward from the fiatface of the gear. In accordance with the invention, the projecting legsof the pole pieces are disposed symmetrically and at right angles to apredetermined polar axis extending diametrically (vertically in FIG. 5)through the central axis of the output shafts. A flat section 56,advantageously of a ferritic magnetic material such as Plastiform (apowdered ferrite in plastic matrix) is received in the channel-likerecess formed by the oppositely disposed pole pieces 54, 55,advantageously such that the pole pieces extend axially slightly beyondthe magnetic element 56, as indicated in FIG. 1. The opposite ends ofthe magnetic element 56 are magnetized in a front-t-o-back direction andreversely at the opposite ends. Thus, for example, the pole piece 54,lying against a south side of the magnetic element, will be stronglypolarized as a south pole, while the pole piece 55, lying against a nortside of the magnetic element, will be strongly polarized as a northpole. The cooperating magnet 51b (not shown in FIG. 5) will, of course,be reversely magnetized, so that its north pole piece cooperates withthe south pole piece 54 of the magnet 51a, when the shafts are in resetpositions.

While other specific forms of reset magnet configurations may beemployed, the above-described arrangement has been found to beparticularly advantageous for the purpose intended, in view of itseconomical construction, flat configuration, and sharply polarizedattraction. Of course, it may not be necessary, insofar as broaderaspects of the invention are concerned, to provide for reset by magneticmeans; where appropriate, suitable spring, gravity, or other resetarrangements may be provided.

In accordance with another aspect of the invention, a novel and highlyeffective arrangement is provided for actuating the control shaft 44between its retracted and operative positions. To this end, a gearsegment 60 is secured to the control shaft 44 and is arranged forcooperation with the gear 39, which is driven directly from the motorpinion 37. The gear segment 60 is provided with gear teeth extendingover somewhat less than 180 of its circumference and is arranged forrotation about an axis concentric with the journal pins 45 of thecontrol shaft.

The rotational orientation of the gear segment 60 with respect to thecontrol shaft 44 is such that, when the control shaft 44 is in itsoperative position, maintaining the reduction train and all gears inmeshing engagement, the gear teeth of the segment are out of mesh withthe teeth of the drive gear 39. T 0 this end, the gear segment 60advantageously is acted upon by an overcentering magnetic detent suchthat, when the control shaft 44 is in its operative position, the teethof the gear segment lie just out of mesh with the drive gear 39, withthe segment being urged by the magnetic detent in a direction to rotatethe segment even further out of mesh. The segment is held in the desiredoperating position, however, by means of a stop lug 61, which is engagedby a stop arm 62 attached to the clapper arm 63 of a control solenoid64.

The, magnetic detent arrangement consists of a first polarized magneticelement 65 secured to the back face of the gear segment 60 and a secondand cooperating polarized magnetic element 66 secured to the front faceof the frame plate 12 in directly opposing relation to the magneticelement 65. The movable magnetic element 65 is polarized north and southalong a diameter, as indiand fixed to the respective output shafts, thehands will be positioned in valid timekeeping positions, when the outputshafts are rotated independently to their respective reset positions.

When the gear reduction train is re-engaged after reset, it is necessaryto retain the necessary mutual relationship between the output shafts-22 while effecting remeshing of the previously disengaged gears.Accordingly, as one of the features of the invention, special provisionsare made, particularly in conjunction with the gear reductioninterconnection between the second hand shaft and the minute hand shaft,and between the minute hand shaft and the hour hand shaft, for effectingremesh of the gear reduction systems in the desired synchronization. Tothis end, the gear and pinion combinations 30, 32 are provided withgears a, 33 of large effective tooth depth and with pinions 31, 34 ofsmaller effective tooth depth. Likewise, the reduction pinions 28, 29,meshing with the gears 30a, 33 respectively, are of large effectivetooth depth, while the drive gears 26, 27, meshing with the pinions 31,34, are of smaller effective tooth depth. Thus, the gear sets of smallereffective tooth depth, which adv'antageou'sly are of fine pitch,stub-tooth form, are arranged to have a depth of mesh less than thedisplacement or throw of the reset control shaft 44, so as to be drawncompletely out of mesh when the control shaft is displaced from itsclosest or operating position to its retracted or reset position, withrespect to the common axis of the output shafts. On the other hand, thegear sets of larger effective depth are provided with teeth of coarsepitch, long-tooth form and are arranged to have an overlap or depth ofmesh somewhat greater than the total displacement of the control shaft44, so that the latter gear sets are maintained in meshing engagement inall rotational positions of the control shaft 44.

Thus, with the above-described relationship between the cooperatinggears of the reduction train, each of the gear and pinion reductioncombinations 30, 32 is maintained in proper meshing relationship withits input gear (i.e., the reduction pinions 28, 29 carried by the secondhand and minute hand shafts 20, 21, respectively). This, alone, is notenough, however, to assure that proper meshing of the reduction traintakes place when the gears subsequently are re-engaged by rotation ofthe eccentric control shaft 44. Thus, in the case of the reductioncombination 30, the input pinion 28 therefor and the output gear 26therefor will occupy definite, predetermined rotary positions followinga resetting operation; however, assuming a typical 8:1 gear reductionratio between the pinion 28 and the gear 30a, the gear 30a may occupyany one of eight different rotary positions when the pinion 28 is in itsdefinite reset position. Accordingly, the pinion 31 of the reductioncombination must be so designed that in any one of those eight positionsthe pinion 31 is in a definite rotary alignment, as regards the teeth ofthe gear 26. In the illustrated example of an 8:1 gear ratio between thepinion 28 and gear 30a, the desired rotary orientation of the pinion 31can be achieved by forming the pinion 31 with eight teeth, or any othernumber of teeth divisible by the number 8. Stated more broadly, thenumber of teeth on the pinion of the reduction combination must be aneven multiple of the previous gear reduction ratio, assuming that onlyone pinion and gear reduction combination is employed between theconnected output shafts. In the principle as thus stated, the term evenmultiple is intended to include the number l as a possible multiplier,as will be understood.

In a typical, practical embodiment of the invention, an overall gearreduction between the second hand shaft 20 and the minute hand shaft 21of 60:1 is achieved advanta'geously by providing an 8:1 reduction ratiobetween the pinion 28 and the gear 30a and a 7.5 :1 reduction ratiobetween the pinion 31 and the gear 26, the pinion 31 being provided withsixteen teeth or a multiple of 2 times the preceding gear reductionratio.

Following the principles set forth above, an overall 6 gear reductionratio between the minute hand shaft 21 and the hour hand shaft 22 of1251 is achieved by providing a 3 :1 reduction ratio between thereduction pinion 29 and the gear 33, and a 4:1 reduction ratio betweenthe pinion 34 and the drive gear 27. Since the first-mentioned reductionratio is 3:1, providing the gear and pinion reduction combination 32with three possible rotary orientations when the minute hand shaft 21 isin its definite reset position, the number of teeth provided on thepinion 34 is a multiple of 3, thirty teeth being provided in a typicalembodiment.

In the illustrated form of the invention, the principles mentionedabove, for providing positive and accurate meshing alignment betweenreduction stages are not necessarily followed with respect to themeshing of the pinion 43 with the drive gear 25, since it is unnecessaryto main tain a definite, geared-together rotary orientation between thesecond hand shaft 20 and any of the drive elements of the input traintherefor. However, it will be apparent that such definite meshingorientations could be provided by an extension of the before-mentionedprinciples, at least when utilizing as a drive motor a synchronousinductor motor of the type described in the before-mentioned RiggsPatent No. 3,014,141 which, through residual magnetic effects, has aplurality of definite stopping posi-' tions. Thus, a typical motor hastwelve distinct stopping positions, enabling the teeth of the drivepinion 37 to be aligned in a known relationship, if the number of teethin the pinion is an even multiple of 12. However, since it isunnecessary, in the illustrated mechanism at least, to provide for adefinite meshing orientation between the pinion 43 and drive gear 25,the additional expense of making such provisionsmay be avoided. In thisrespect, the fact that the motor 12 stops in any one of twelve distinctpositions, rather than a single, definite reset position, coupled withthe fact that the overall gear reduction ratio between the motor shaft36 and the second hand 20 is 250:1, introduces unusually high multiplesinto the before-mentioned formulas for determining the proper number ofgear teeth in the reduction stages. Thus, it is expeditious andpractical, at least in a clock mechanism, to omit providing for adefinite meshing orientation between the pinion 43' and the drive gear25 at the end of reset, particularly since no difficulty is experiencedin bringing an already rotating pinion 43 into driving mesh with thegear 25 when the control shaft 44 is operated to engage the gear train.

Advantageously, the gear and pinion reduction combination 41, formingpart of the reduction train driving the second hand drive gear 25, is soconstructed that the gear 42 and its driving pinion 40 are provided withteeth of coarse pitch, long-tooth form and are arranged to have anoverlap somewhat greater than the total displacement of the controlshaft 44. At the same time, the pinion 43 and the drive gear 25 areprovided with teeth of fine pitch, stub-tooth form, arranged to have adepth of mesh less than the displacement of the control shaft, so as tobe drawn completely out of mesh when the control shaft isrotated to aretracted position, permitting free rotation of the second hand shaft 20to its predetermined reset position.

In accordance with one of the specific features of the invention, noveland particularly advantageous arrangements are provided forindependently returning each of the output shafts 20-22 to theirrespective reset positions, when the output shafts are released bydisengagement of their respective drive gears 25-27. To this end, eachof the output shafts carries a polarized magnet 50a52a. Advantageously,the magnets 51a, 52a are mounted on the respective drive gears 26, 27for the minute hand and hour hand shafts 21, 22, while the magnet 50a issecured to a disk 53 fixed to the end of the second hand shaft 20. Eachof the polarized, rotating magnetsSOa-SZa cooperates with a similarlypolarized but fixed magnet 50b 52b, substantially as indicated inFIG. 1. The fixed magcated by the N and S designations shown in brokenlines in FIG. 3. Likewise, the fixed magnetic element 66 is polarizednorth and south along a diameter, as indicated by the N and Sdesignations shown in full lines in FIG. 3. The relative orientation ofthe axes of polarization of the magnetic elements 65, 66 are such that,as shown in FIG. 3, when the stop lug 61 is seated against the stop arm62, the north pole of the movable magnet 65 is adjacent the north poleof the fixed magnet 66, but is slightly offset therefrom in a directionsuch that the repelling forces of the like magnetic poles tend to seatthe stop lug 61 firmly against the stop arm 62. Similarly, the southpoles of the magnetic elements exert repelling forces tending to seatthe stop lug 61. Accordingly, when the mechanism is conditioned as shownin FIG. 3 the gear segment 60 is effectively held in a fixedposition,with its gear teeth just out of mesh with the drive gear 39 inthe direction in which the segment is urged by the repelling magneticforces.

Advantageously, the energizing circuit forthe solenoid 64 is connectedin parallel with the energizing circuit for the main drive motor 35, andboth the solenoid and drive motor are connected to the power sourcethrough an appropriate switching arrangement, indicated schematically at67, under the control of a master timer 68. Accordingly, when the switch67 is opened by the master timer, the energizing circuits for thesolenoid 64 and drive motor 35 simultaneously are interrupted.

When the power circuit is interrupted, the motor 35, and

therefore the drive gear 39, immediately stop. At the 7 same time, thesolenoid 64 is de-energized, releasing its clapper arm 63 and permittingits stop arm 62 to be retracted by a spring 69 (FIG. 2). This releasesthe gear segment 60 for rotation due to the combined repelling andattracting forces of the magnetic elements 65, 66. As will beunderstood, the magnetic elements 65, 66 will exert a rotating torqueupon the gear segment 60, tending to bring the north pole of the gearsegment into polar alignment with the south pole of the fixed magneticelement 66, and vice versa. This causes the gear segment 60 and theattached eccentric control shaft 44-to be rotated substantially through180, whereby the pinions 43, 31, and 34 are retracted out of mesh withthe respective drive gears 2527, the gears 42, 30a, and 33 remaining inat least partial mesh, however, due to their longer tooth form, aspreviously explained, The described relationships are evident in FIGS. 3and 4. i In accordance with the invention, the arc over which the teethof the gear segment 60 extend is such, in relation to the tooth form,gear diameter, etc., that rotation of the gear segment 60 throughsomewhat less than 180 '(e.g., about 160l65) will bring the gear segmentfrom a position in which the trailing teeth of the segment are just outof mesh with the drive gear 39 into a position in which the leadingtooth of the segment is abutting a tooth of the drive gear 39, at leastsubstantially in meshing relationship. The arrangement is such that theleading tooth of the gear segment engages a tooth of the drive gear 39in a rotational orientation of the gear segment in which the magneticpoles thereof have not yet been brought into alignment with the oppositepoles of the fixed magnetic element 66. Thus, as shown in FIG. 4, whenthe first tooth of the gear segment engages a tooth of the drive gear39, the gear segment 60 issubject to strongly attractive magnetic forcesof the misaligned, unlike poles of the respective magnetic elements 65,66, tending to rotate the gear segment in a direction which will carrythe segment into meshing relationship with the drive gear 39. However,since the drive gear 39 is at that time stopped, the gear segment 60will be held motionless, retaining the control shaft 44 in its retractedor reset position, in which all of the output shafts 20-22 aredisengaged and permitted to return to a predetermined reset condition.

Subsequently, when the power source is reconnected to the motor 35 andsolenoid 64, by action of the master timer 68 closing the switch 67',the motor 35 is energized to drive the gear 39 in a counterclockwisedirection, as viewed in FIG. 4. The magnetically applied torque actingon the gear segment is sufiicient to insure positive meshing engagementof the segment 60 and drive gear 39, as the gear 39 starts to rotate,and the segment thereafter is driven positively by the gear 39 throughan angle somewhat in excess of 180, until the poles of the movablemagnetic element are driven into and beyond aligned relation with likepoles of the fixed magnetic element 66. With continued rotation of thedrive gear'39, the last tooth of the gear segment 60 ultimately passesout of mesh with the drive gear, at which time the gear segment 60 isacted upon essentially by the repelling influence of like magnetic polesof the elements 65, 66, so that the gear teeth are completely cleared.At this point, the stop lug 61 moves into engagement with the stop arm62, which had been returned to its active or blocking position byenergization of the control solenoid 64 simultaneously with that of themotor 35.

Advantageously, to assure uniformly reliable operation of the magneticdetent acting upon the gear segment 60 and to assure proper meshing ofthe gear segment and its drive gear 39 upon resumption of energization,following reset, arrangements are provided for reliably assuring thatthe drive gear 39 will have a substantially definite or fixedrelationship to the gear segment 60 during a reset interval. To thisend, specifically advantageous use is made of an inductor typesynchronous motor of the type described in the before-mentioned RiggsPatent No. 3,014,141, which has definite stopping positions. Thus, in atypical practical embodiment of the invention, the motor 35 has twelvedefinite stopping positions in which it may come to rest uponde-energization. Thus, by providing the motor pinion 37 with apredetermined number of teeth, constituting an even multiple of thenumber 12, the motor pinion 37 always will come to rest with its teethin a specific, predetermined orientation. Typically, but notnecessarily, twelve teeth are used on the motor pinion 37, since this isthe lowest number capable of use with a motor having twelve stoppingpositions.

One of the significant advantages to the control arrangement described,for manipulating the eccentric control shaft 44 in accordance with theenergized and de-energized conditions of the mechanism, resides in thefact that the control solenoid 64 does not have to perform work upon thecontrol shaft. This is of particular significance in clock applications,for example, where the size and cost of the solenoid 64 must. bemaintained at a practical minimum and where inrush currents should bekept as low as possible. Thus, if the solenoid 64 were required to dowork in closing, as by utilizing the solenoid to effect movement of theeccentric control shaft 44, not only would the solenoid have to besubstantially larger and more costly, but significant amounts ofenergizing current would be required during the closing interval. Withthe mechanism of the invention, on the other hand, the control solenoid64 operates only against a very light spring 69 and performs no workwhatever upon the control shaft 44. Rather, it simply positions the stoparm 62 to intercept the stop lug 61, after the lug has passed throughits magnetic overcenter position established by the orientation of thepolarized magnetic elements 65, 66. All of the work required to drivethe gear segment 60 to its overcentered, operative position is derivedfrom the motor 35, which does not require a large inrush current toperform the necessary work and, moreover, is at that time disconnectedfrom the load of the reduction train and output shafts.

T e mechanism of the invention is uniquely adapted for use as a slaveclock unit which, at a predetermined time of day, is reset precisely inaccordance with the operation of a master clock. The necessary resettingis effected by interrupting the energy supply to the motor 35 iii andcontrol solenoid 64 for a'few seconds, sufiicient to effect thesubstantially instantaneous disconnection of the reduction gear trainand rotation of the output shafts to their respective reset positions.At a predetermined reset time, corresponding to the reset indication ofthe slave unit, energization is restored to the control solenoid anddrive motor, so that the slave unit resumes operation in exactsynchronism with the master timekeeping control.

It should be understood, however, that the form of the invention hereinspecifically illustrated and described is intended to be representativeonly, as certain changes may be made therein without departing from theclear teachings of the disclosure. Accordingly, reference should be madeto the following appended claims in determining the full scope of theinvention.

What is claimed is:

1. A resettable gear mechanism comprising (a) a first output shaft,

(b) a second output shaft,

(c) reduction gearing interconnecting said output shafts for outputrotation at different but related rotational speeds,

(d) said reduction gearing including a coaxially mounted gear and pinioncombination and also including a related pinion connected to one of saidoutput shafts and a related gear connected to the other of said outputshafts, the gear element of said combination being arranged for meshingengagement with said related pinion and the pinion element of saidcombination being arranged for meshing engagement with said relatedgear,

(e) reset shift means operable to a reset'condition to shift at leastone of the elements of the gear and pinion combination relative to itsrelated gear or pinion to a position in which said one element is out ofmesh with its related gear or pinion while the other element of saidcombination remains in mesh with its related gear or pinion, and

(f) means operative to rotate said output shafts independently of saidreduction gearing to predetermined reset positions while said resetshift means is in its reset condition,

(g) said one element being restored to meshing engagement with itsrelated gear or pinion upon return of said reset shift means to anoperating condition.

2. The resettable gear mechanism of claim 1, in which (a) the number ofteeth on said one element of the gear and pinion combination is an evenmultiple of the number of possible rotary positions which may be assumedby the said one element when the output shaft connected to the relatedgear or pinion for the other of said elements is rotated to itspredetermined reset position.

3. The resettable gear mechanism of claim 1, in which (a) said oneelement of the gear and pinion combination is the pinion element, and

(b) the number of teeth on said pinion element is an even multiple ofthe gear ratio between the ,gear element of said combination and itsrelated pinion.

4. The resettable gear mechanism of claim 1, in which (a) said gear andpinion combination is mounted on a common shaft, and

(b) said reset shift means comprises said common shaft and means forshifting said common shaft in a radial direction toward and away fromthe related gear or pinion cooperating with said one element of the gearand pinion combination.

5. The resettable gear mechanism of claim 4, in which (a) said relatedgear and pinion are mounted for rotation on a common axis,

(b) the teeth of said one element of the gear and pinion combination areof less effective depth than the teeth of the other element of thecombination, and

(c) said reset shift means is operable through a predetermined limiteddistance so related to the effective depth of the teeth of said gear andpinion elements that the teeth of said one element are shifted out ofmesh while the teeth of the other element remain in mesh.

6. The resettable gear mechanism of claim 4, in which (a) journal meansare provided for mounting said common shaft for rotation independentlyof said gear and pinion combination and about an axis offset from theaxis of rotation of said combination,

(b) said reset shift means includes means for rotating said common shaftthrough a substantial angle.

7. The resettable gear mechanism of claim 6, in which (a) an input drivemotor is controllably associated with one of said output shafts, and

(b) said means for rotating said common shaft comprises meanscontrollably associated with said drive motor.

8. The resettable gear mechanism of claim 7, in which (a) a gear segmentis mounted on said common shaft,

(b) a drive gear is connected to said motor and is engageable with theteeth of said gear segment when said gear segment is in predeterminedrotary orientation,

(c) yieldable detent means operative when said motor is deenergized tourge said gear segment in its driven direction into initial meshingengagement with said drive gear, whereby said gear segment is drivenupon energization of said motor,

(d) said yieldable detent means being further operative when said gearsegment is driven through its predetermined range of meshing engagementto urge the segment in its driven direction, toward meshing engagementwith said drive gear,

(e) stop means are provided to engage said gear segment for limiting itsrotation in the driven direction under the urging of said detent means,and

(f) solenoid control means are associated with the energizing circuitfor said motor for shifting. said stop means to operative position, whensaid motor is energized, and to inoperative position when said motor isdeenergized.

9. The resettable gear mechanism of claim 8, in which said yieldabledetent means comprises (a) a first polarized magnet mounted in fixedrelation adjacent said common shaft and having its polar axisintersecting the axis of rotation of said shaft, and

(b) a second polarized magnet carried by said common shaft andcooperatively aligned and related to said first magnet whereby, in anyrotary position of said common shaft, said second magnet and said commonshaft are urged toward a position of predetermined rotary alignment.

10. A resettable clock, comprising (a) a plurality of concentricallyjournalled time indicating output shafts, including a low speed shaftand one or more higher speed shafts,

(b) a drive gear fixed to each of saidoutput shafts,

(c) a reduction pinion fixed to the drive gear for each of the higherspeed shafts,

(d) a transmission shaft mounted in parallel relation to the common axisof said output shafts,

(e) a gear and pinion reduction combination connecting the reductionpinion of each higher speed shaft to the drive gear for the shaft of thenext lower speed,

(f) each of said gear and pinion combinations being mounted for rotationon said transmission shaft,

(g) the pinions of each reduction combination having teeth of lesseffective depth than the teeth of the gears of such combinations,

(h) reset shift means operable for controllably moving said transmissionshaft away from said common axis a distance sufficient to disengage thepinions of said reduction'combinations from the drive gears for therespective lower speed shafts but insufficient to 13 disengage the gearsof said reduction combinations from the pinions of the respective higherspeed shafts, and

(i) rrieans aetin'g individually on said output shafts when said resetshift means is operated to urge the output shafts disenga ed thereby topredetermined rotary positions.

111' The resettable clock of claim 10, in which (a) the saidpredetermined positions to which the respective' disengaged shaftsareurged are mutually consisteiit with gear reduction relationshipsprovided by said pinions and gears for timekeeping opera- I tion, and

(b) each pinion of each of said gearand pinion combinations has apredetermined number of gear teeth, which number is an event multiple ofthe reduction ratio between the gear of the same combination and thepinion of the next higher speed shaft.

12; In resettable apparatus; I

(a) an output shaft and a transmission shaft in spaced parallelrelationship with each other,

(b) reduction gearing including first .gear means mounted on said outputshaft and second gear means mounted on said transmission shaft forinterconnecting the same,

(a) reset shift means for movingrsaid transmission shaft away from said.output shaft a distance sulficient to disengage at least portions ofsaid reduction gearing,

(d) an electric drive motor for supplying driving power to said outputshaft, and

(e) means for interconnecting said drive motor and the reset shift meansfor said transmission shaft whereby, upon energization of said motor,said transmission shaft is shiftedto a position in which said reductiongearing maintains said shafts in interconnected relation and, upondeenergization of said motor, said transmission shaft is shiftedto aposition in which the said portions of said reduction gearing aredisengaged, 4 I

(f) at least one of the shifting movements of said transmission shaftbeing effected by the power of said motor. r

13. The resettable apparatus of claim 12 which comprises I I (a) amovable polarized magnet carried by said output shaft, and I I I (b) astationary polarized magnet mounted in close axial proximity to themovablemagnet, whereby con- I stantlyto urge the movable magnet and theoutput II shaft fixed thereto to a predetermined rotary position. II 14,The resettable apparatus of claim 13, in which each of saidpolarizedmagnets comprises I I I I (a) spaced opposed magnetic poles disposed inprede- I .termined radially spaced relation to the axis of rotation ofsaid output shaft, I

(b) said poles being symmetrically arranged with respect to ,said axisof rotation and being of linear configuration and disposed along linessubstantially at right angles to a polar axis extending through said Iaxis of rotation. I

15, A resettable clock comprisin I I (a) a plurality of time indicatingoutput shafts, in-

eluding a low speed shaft and one or more shafts of successively higherspeeds, I

(M a drive gear associatedwith each of said shafts for imparting rotarydrivingmotion thereto,.

(c) a reduction, pinion associated with each of the higher speed shafts,I

(d) an input drive including an electric motor for .said clock, I I II I(e) connectinggear means for operatively connecting the drive gears ofthe lower speed shafts each to the reduction pinion of the shaft of thenext higher speed and for operatively connecting the drive gear of thehighest speed shaft to said input drive,

(f) reset shift means including a solenoid operative when deenergized to.controll-ab ly disengage said connecting gear means from said drivegears while maintaining engagement between said connecting gear meansand said reduction pinions and said input drive, said solenoid beingoperative when energized to. cause engagement of said connecting gearmeans with said drive gears, I I I (g) reset means acting on therespective shafts when said connecting gear means are so disengaged torotate said shafts separately to predetermined positions, and

(h) means for energizing said motor and said solenoid from a commonsource of energizing power, whereby said motor and said solenoid areenergized and deenergized substantially simultaneously.

16. The resettable clock of claim 15, in which I (a) said reset shiftmeans includes means driven by said motor, whereby the effective workinput to said reset shift means is substantially isolated from saidsolenoid.

17. A resettable clock, comprising (a) a plurality of concentricallyjournalled time indicating output shafts, including a low speed shaftand one or more higher speed shafts,

(b) a drive gear fixed to each of said output shafts,

(c) a reduction pinion fixed to the drive gear for each of the higherspeed shafts, I

(d) a transmission shaft mounted in parallel relation to the common axisof said output shafts;

(e) a gear and pinion reduction combination connecting the reductionpinion of each higher speed shaft to the drive gear for the shaft of thenext lower speed, I

(f) each of said gear and pinion combinations being mounted for rotationon said transmissionshaft,

(g) the pinions of each reduction combination having teeth of lesseffective depth than the teeth of the gears of such combinations,

(h) reset shift means operable for controllably moving said transmissionshaft away from said common axis a distance sufficient to disengage thepinions of said reduction combinations from the drive gears for therespective lower speed shafts but insufficient to disengage the gears ofsaid reduction combinations fromthe pinions of the respective higherspeed shafts,

(i) means acting individually onsaid output shafts when said reset shiftmeans is operated to urge the output shaftsdisengaged thereby topredetermined rotary positions, I

(j) an electric drive motor for supplying driving power to the highestspeed output shaft, and I (k) means for interconnecting said drive motorand the reset shift means for said transmission shaft whereby, uponenergization of said motor, said transmission shaft is shifted to aposition engaging the output shafts in interconnected relation and, upondeenergization of said motor, said transmission shaft is shifted to aposition disengaging the outpu-tshafts, I I II I I (l) at least one ofthe shiftingmovements of said transmission shaft being effected by thepower of .said motor. I I

18. A resettable clock, comprising I Y (a) a plurality of concentricallyjournalled time indicating output shafts, including a low speed shaftand one or more higher speed shafts,

(b) a drive gear fixed to each of said output shafts,

(c) a reduction pinion fixed to the drive gear for each of the higherspeed shafts,

(d) a transmission shaft mounted in parallel relation to the common axisof said output shafts,

(e) a gear and pinion reduction combination connecting the reductionpinion of each higher speed shaft to the drive gear for the shaft of thenext lower speed,

(f) each of said gear and pinion combinations being mounted for rotationon said transmission shaft,

(g) the pinions of each reduction combination having teeth of lesseffective depth than the teeth of the gears of such combinations,

(h) reset shift means operable for controllably moving said transmissionshaft away from said common axis a distance sufficient to disengage thepinions of said reduction combinations from the drive gears for therespective lower speed shafts but insufficient to disengage the gears ofsaid reduction combinations from the pinions of the respective higherspeed shafts,

(i) means acting individually on said output shafts when said resetshift means is operated to urge the output shafts disengaged thereby topredetermined rotary positions,

(j) an electric drive motor for supplying driving power to the highestspeed output shaft,

(k) means for interconnecting said shaft motor and the reset shift meansfor said transmission shaft whereby, upon energization of said motor,said transmission shaft is shifted to a position engaging the outputshafts in interconnected relation and, upon deenergization of saidmotor, said transmission shaft is shifted to a position disengaging theoutput shafts,

(l) at least one of the shifting movements of said transmission shaftbeing effected by the power of said motor,

(In) said reset shift means including a shift element adapted to bedriven in a cyclical manner by said drive motor,

(n) yieldable overcentering means acting on said shift element to urgesaid element from any position in its cyclical path to a predeterminedposition, and

(o) controllable solenoid actuated stop means operable to restrain saidshift element in a fixed operative position displaced from saidpredetermined position,

(p) said stop means being retractable when said motor is deenergized toaccommodate movement of said shift element by said overcentering meansinto driving relationship with said motor,

(q) said motor and said shift element being so related that, uponenergization of said motor, said shift element is driven through morethan one half of its cycle and through a'predetermined overcenteringposition, 7

(r) said shift element automatically being moved out of drivingrelationship with said motor upon said shift element being driventhrough said overcentering position,

19. A resettable' clock, comprising (a) a plurality of concentricallyjournalled time indicating output shafts, including a low speed shaftand one or more higher speed shafts,

.(b) first and second drive gears respectively 'afiixed to said outputshafts,

(c) a reduction pinion fixed to the drive gear for each of the higherspeed shafts, (d) a transmission shaft mounted in parallel relation tothe common axis of said output shafts,

(e) a gear and pinion reduction combination connecting the reductionpinion of each higher speed shaft to the drive gear for the shaft of thenext lower speed,

(f) each of said gear and pinion combinations being respective lowerspeed shafts but insufiicient to disengage the gears of said reductioncombinations from the pinions of the respective higher speed shafts,

(i) means acting individually on said output shafts when said resetshift means is operated to urge the output shafts disengaged thereby topredetermined rotary positions,

(3') an electric drive motor for supplying driving power to the highestspeed output shaft,

(k) means including a third drive gear for interconnecting said drivemotor and the reset shift means for said transmission shaft whereby,upon energization of said motor, said transmission shaft is shifted to aposition engaging the output shafts in interconnected relation and, upondeenergization of said motor, said transmission shaft is shifted to aposition disengaging the output shafts.

(l) at least one 'of the shifting movements of said transmission shaftbeing effected by the power of said motor,

(rn) said reset shift means including a gear segment adapted to bedriven in a cyclical manner by said third drive gear,

(n) yieldable overcentering means acting on said gear segment to urge:said segment from any position in its cyclical path to a predeterminedposition, and

(o) controllable solenoid actuated stop means operable to restrain saidgear segment in a fixed operative position displaced from saidpredetermined position,

(|p) said stop means being retractable when said motor is deenergized toaccommodate movement of said gear segment by said overcentering meansinto driving engagement with said third drive gear,

(q) said gear segment and said third drive gear being so related that,upon ener-gization of said motor, said gear segment is driven by saidthird drive gear through in excess of degrees of rotation of said gearseg- 1116121? and through a predetermined overcentering position, i

(r) said gear segment and said third drive gear automatically beingdisengaged upon said gear segment being driven through saidovercentering position.

20. A resettable clock comprising i (a) a' plurality of time indicatingoutput shafts, in-

cluding a low speed shaft and one or more shafts of successively higherspeeds,

(b) a drive gear associated with each of said shafts for impartingrotary driving motion thereto,

(c) a reduction pinion associated with each of the higher speed shafts,

(d) an input drive for said clock, 7

(e) connecting gear means for operatively connecting the drive gears ofthe lower speed shafts each tothe reduction pinion of the shaft of thenext higher speed and for operatively connecting the drive gear of thehighest speed shaft to said input drive,

(f) reset shift means for controllably disengaging said connecting gearmeans from said drive gears while maintaining engagement between saidconnecting gear means and said reduction pinions and said input drive,and

(g) reset means acting on the respective shafts when said connectinggear means are so disengaged to rotate said shafts separately topredetermined positions,

(h) said reset means including, a movable polarized magnet carried byeach of said output shafts and a stationary polarized magnet for each ofsaid movable magnets mounted in close axial proximity thereto, wherebyconstantly to urge the movable magnet'and the output shaft fixed theretoto a predetermined rotary position, v (i) each of said movable andstationarypolarized magnets having an elongated pole piece of generallyL- shaped cross-section disposed ,with one leg of the L in a planenormal to the corresponding output shaft (j) a cooperating pair of saidmovable and stationary 1 7 polarized magnets comprising a pair ofaxially spaced L-shaped pole pieces arranged with their respective otherlegs projecting toward each other and arranged to be brought intoaligned, facing relationship.

21. In resettable apparatus,

(a) an output shaft and a transmission shaft in spaced parallelrelationship With each other,

(b) reduction gearing including first gear means mounted on said outputshaft and second gear means mounted on said transmission shaft forinterconnecting the same,

(c) reset shaft means for moving said transmission shaft in a radialdirection away from said output shaft a distance sufficient to disengageparticular portions of said reduction gearing but insufiicient todisengage other portions of said reduction gearing,

(d) an electric drive motor for supplying driving power to said outputshaft, and

(e) means for interconnecting said drive motor and the reset shift meansfor said transmission shaft whereby, upon energization of said motor,said transmission shaft is shifted to a position in which said 20 LEOSMILOW, Primary Examiner.

LEYLAND M. MARTIN, Examiner.

reduction gearing maintains said shafts in interconnect'ed relation and,upon deenergization of said motor, said transmission shaft is shifted toa position in which said particular portions of said reduction gearingare disengaged while said other portions remain in engagement,

(f) at least one of the shifting movements of said transmission shaftbeing effected by the power of said motor.

References Cited by the Examiner UNITED STATES PATENTS 1,957,543 5/1934Kenerson 58-26 X 3,090,191 5/ 1963 Montgomery 58-34 3,112,069 11/ 1963Truesdell et a1. 235-144 FOREIGN PATENTS 1,282,670 12/ 1961 France.

1. A RESETTABLE GEAR MECHANISM COMPRISING (A) A FIRST OUTPUT SHAFT, (B)A SECOND OUTPUT SHAFT, (D) REDUCTION GEARING INTERCONNECTING SAID OUTPUTSHAFTS FOR OUTPUT ROTATION AT DIFFERENT BUT RELATED ROTATIONAL SPEEDS,(D) SAID REDUCTION GEARING INCLUDING A COAXIALLY MOUNTED GEAR AND PINIONCOMBINATION AND ALSO INCLUDING A RELATED PINION CONNECTED TO ONE OF SAIDOUTPUT SHAFTS AND A RELATED GEAR CONNECTED TO THE OTHER OF SAID OUTPUTSHAFTS, THE GEAR ELEMENT OF SAID COMBINATION BEING ARRANGED FOR MESHINGENGAGEMENT WITH SAID RELATED PINION AND THE PINION ELEMENT OF SAIDCOMBINATION BEING ARRANGED FOR MESHING ENGAGEMENT WITH SAID RELATEDGEAR, (E) RESET SHIFT MEANS OPERABLE TO A RESET CONDITION TO SHIFT ATLEAST ONE OF THE ELEMENTS OF THE GEAR AND PINION COMBINATION RELATIVE TOITS RELATED GEAR OR PINION TO A POSITION IN WHICH SAID ONE ELEMENT ISOUT OF MESH WITH ITS RELATED GEAR OR PINION WHILE THE OTHER ELEMENT OFSAID COMBINATION REMAINS IN MESH WITH ITS RELATED GEAR OR PINION, AND(F) MEANS OPERATIVE TO ROTATE SAID OUTPUT SHAFTS INDEPENDENTLY OF SAIDREDUCTION GEARING TO PREDETERMINED RESET POSITIONS WHILE SAID RESETSHIFT MEANS IS IN ITS RESET CONDITION, (G) SAID ONE ELEMENT BEINGRESTORED TO MESHING ENGAGEMENT WITH ITS RELATED GEAR OR PINION UPONRETURN OF SAID RESET SHIFT MEANS TO AN OPERATING CONDITION.